Apparatus for drilling and routing truss joist chords



United States Patent Inventor Arthur L. Troutner Skyline Drive, Boise, Idaho Appl. No. 781,057

Filed Dec. 4, 1968 Patented Dec. 1, 1970 APPARATUS FOR DRILLING AND ROUTING TRUSS JOIST CHORDS 6 Claims, 18 Drawing Figs.

U.S. Cl. 144/3, 144/35,144/136 Int. Cl B27m 3/00 Field of Search 144/35,

[56] References Cited UNITED STATES PATENTS 359,453 3/1887 Linn 144/3 2,790,470 4/1957 Graham 144/3 Primary Examiner-Donald R. Schran Attorney-Eugene D. Farley ABSTRACT: An elongated framework adjustably supports drilling and routing components and a plurality of longitudinally spaced stops by which a truss joist chord is advanced stepwise to selected positions at which it is drilled transversely and routed in the drilled areas. Each stop succeeding the first utilizes a previously drilled opening to position the chord for subsequent drilling and routing operations. The router component includes means for varying the width of the rout in correspondence with the size of the associated drill opening.

Patented Dec. 1, 1970 3,543,818

Sheet 1 of 6 IIIIII IHIL F lllllll uh. I U H ARTHUR TROUTNER INVENTOR,

ATTY.

Patent ecl; Dec. 1, 1970 3,543,818

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Sheet RR 3 2 0 I m m w v oE 1 mm; L w u Alllo V R o. wmmf W W ///Z/A WAR M E I I I Ill f Patented Dec. 1, 1970 3,543,818

Sheet 4' of 6 ,se I32 FIG. 576 84 FIG. 9

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ARTHUR L. TROUTNER INVENTOR.

ATTY.

Patented Dec. 1,1970 3,543,818

1"" I L ARTHUR L. TROUTNER 9 INVENTOR. FIG. 8 BY ATTY Patented Dec. 1, 1970 Sheet ARTHUR l v TROUTNER INVENTOR.

BY fi ATTY.

wwm S- HQ on APPARATUS FOR DRILLING AND ROUTING TRUSS JOIST CHORDS BACKGROUND OF THE INVENTION This invention relates to the manufacture of truss joists, and more particularly to apparatus for drilling and routing the chords of a truss joist at selected longitudinally spaced positions.

In the manufacture of truss joists in which spaced chords are interconnected by a zigzag pattern of webs, it is necessary to drill the chords at longitudinally spaced intervals, predetermined by the type and size of truss joists, to receive the anchor pins for the webs, and to rout the chords in the drilled areas to accommodate the lapped ends of the webs.

It is generally accepted practice that the end anchor pins are of larger size than the intermediate ones, thereby requiring the end drill openings to be of larger diameter and the associated routings to be of greater width, than the intermediate drill openings and routings.

The foregoing operations heretofore have been accomplished by physically marking the drilling and routing positions on the chords and manually manipulating the latter relative to drilling and routing devices, or by the use of templates prepared for each size and type of truss. These procedures are time consuming and therefore costly, and they are susceptible of human error as to the size and position of drill openings and routings.

Apparatus provided heretofore utilize adjustable stops by which a chord is advanced stepwise to selected positions at which it is drilled transversely and routed in the drilled areas. Although such apparatus increases materially the degree of accuracy of locating the drilling and routing positions and reduces production time, the element of human error still prevails in connection with the sizes of drill openings and routings.

SUMMARY OF THE INVENTION In its basic concept the apparatus of the present invention provides for the stepwise advancement of a truss joist chord to selected positions at which it is drilled transversely and routed in the drilled areas, with the width of the routings being adjusted automatically in correspondence with the size of the associated drill opening.

It is by virtue of the foregoing basic concept that the principal objective of the present invention is achieved, namely to overcome the disadvantges of prior procedures and apparatus, as enumerated hereinbefore.

Another important object of the present invention is to provide apparatus of the class described which includes a single adjustment by which to vary longitudinal spacing between drill openings and routings in a chord, whereby to accommodate the manufacture of truss joists of varying types and sizes.

The foregoing and other objects and advantages of the present invention will appear from the following detailed description taken in connection with the accompanying drawings of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary plan view of apparatus embodying the features of the present invention.

FIG. 2 is a vertical section taken on the line 2-2 in FIG. 1. FIG. 3 is a fragmentary foreshortened sectional view taken on the line 3-3 in FIG. 1.

FIG. 4 is a fragmentary sectional view taken on the line 4-4 in FIG. 3.

FIG. 5 is a fragmentary sectional view taken on the line 5-5 in FIG. 1.

FIG. 6 is a fragmentary sectional view taken on the line 6-6 in FIG. 1.

FIG. 7 is a fragmentary sectional view taken on the line 7-7 in FIG. 1, the router being shown retracted in solid lines and in operative position in broken lines.

FIG. 8 is a fragmentary plan view, partly in section, of the router component of the apparatus.

FIG. 9 is a fragmentary sectional view taken on the line 9-9 in FIG. 8.

FIG. 10 is a fragmentary sectional view taken on the line 10-10 in FIG. 8.

FIG. 11 is a fragmentary sectional view taken on the line 11-11 in FIG. 8.

FIG. 12 is a fragmentary sectional view taken on the line 12-12 in FIG. 1.

FIG. 13 is a fragmentary plan view of the micrometer ad- 10 justment for the carriage component of the apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT The components of the apparatus are mounted upon a frame work 10 which supports a pair of laterally spaced, elongated rails 12 and 14. At the infeed end of the framework is mounted a horizontal roller 16 for supporting a truss joist for movement through the apparatus. A vertical roller 18 is mounted adjacent one end of the horizontal roller and projects upwardly therefrom to engage a side edge of the joist, to

position the latter for movement through the apparatus along a fixed reference line.

Downstream from the infeed rollers the framework supports a drilling component. Since it is desirable to be able to provide the joist with drill openings of at least two sizes, the drilling component includes a pair of drill assemblies 20 and 22, each for a different size of drill. Since the drill assemblies are identical, only the right hand assembly 22 shown in F IG. 1 is desired herein in detail, with particular reference to FIG. 3. Corresponding components of the left hand drill assembly are identified by the same reference numerals carrying a prime superscript.

The drill assembly includes an electric motor bolted or otherwise secured to the outer end of an elongated hollow cylindrical housing 26 which is mounted on the framework and extends laterally with respect to the longitudinal direction of the rails. The inner end of the housing terminates short of the longitudinal center line between the rails, to permit the passage of a truss joist chord C between the laterally spaced inner ends of the pair of housings.

The output shaft 28 of the motor is connected by a coupling 30 to an elongated spline shaft 32 which extends into the housing. Mounted on the spline shaft for rotation therewith, but also for longitudinal movement relative thereto, is a ball spline bearing 34 of conventional construction. This bearing is secured, as by the setscrew 36, within the hollow coupling 38. The inner end of the coupling has athreaded opening which receives the threaded outer end of the drill spindle 40. The outer portion of the spindle is hollow to freely receive therein the inner end portion of the spline shaft. The inner end of the spindle has a threaded section of reduced diameter adapted to mount a conventional drill bit chuck 42 for supporting a conventional drill bit 44.

A hollow sleeve 46 freely surrounds the intermediate portion of the spindle and is provided with threaded endsections to which are secured the retracting piston 48 and the advancing piston 50, respectively. These pistons are spaced longitudinally at opposite sides of the fixed seal 52 which is secured within the cylindrical housing 26. The spaces between the fixed seal and the pistons accommodate fluid pressure selectively through conduits 54 and 56 (FIG. 4) to effect retraction or advancement of the drill bit relative to a truss joist chord.

Bearings interposed between the pistons and spindle accommodate rotation of the latter relative to the pistons, as will be understood. A bearing 58 at the inner end of the cylindrical housing supports the drill bit for rotation and longitudinal movement relative to the housing.

The retracting piston 48 associated with each drill assembly is provided with an outwardly extending skirt portion 60. The skirt portion is provided with a pair of longitudinally spaced annular grooves which provides cam surfaces 62 and 64. During movement of the retracting piston these surfaces function to engage selectively the actuating arms of associated electric switches, for purposes explained in detail hereinafter.

Referring to FIG. 5, the laterally spaced inner ends of the cylindrical housings 26 are interconnected by a rectangular housing 66 the open upper end of which is removably closed by a cover plate 68. This cover plate supports a downwardly depending cylinder 70. The open bottom end of the cylinder slilably received the piston 72 the lower end of which is secured to the upper clamp plate 74. The space between the piston head and the cylinder is adapted to receive fluid pressure from the supply conduit 76 for moving the piston downward. A stem 78 secured to the plate 68 and extending through an opening in the piston head, is provided at its lower end with an enlarged head 80 for abutment by one end of a coil spring 82. The opposite end of the spring engages the piston head, whereby to urge the piston resiliently upward to effect retraction of the upper clamp plate.

One or more elongated fingers 84, secured to the piston head, project upward through openings in the top plate 68 to prevent rotation of the piston and hence maintain proper alinement of the upper clamp plate with the lower clamp plate.

The lower clamp plate 86 is secured to the upper end of a piston rod 88 which extends downward slidably through a sleeve 90 supported by the framework 10. The rod supports a piston 92 at its lower end. The piston is confined slidably in a cylinder 94 extending downward from the sleeve. The space between the piston and the cylinder is adapted to receive fluid pressure from the conduit 96 to elevate the lower clamp plate toward the upper clamp plate. Spring 98, between the piston and sleeve, functions to retract the lower clamp plate. A lug 100 on the framework slidably engages the lower clamp plate I to maintain the latter in proper alinement with the upper clamp plate.

The piston 72 associated with the upper clamp plate is larger than the piston 92 associated with the lower clamp plate. Accordingly, the greater downward force operates to press the chord firmly against the fixed horizontal index roller 102. The chord thus is positioned with its bottom surface a fixed distance below the axis of the drills 44 or 44'.

Fixed reference line rollers 104 are supported by the housing 66, as are associated spring loaded press rollers 106 which engage the opposite side of the chord, to urge the latter resiliently into abutment with the reference line rollers.

The clamp plates function to secure releasably between them the truss joist chord C to be drilled by operation of either one of the pair of drill assemblies previously described.

Abutment means is providedfor engaging the leading end of a truss joist chord downstream from the drill assemblies, to

position the chord properly for drilling the first hole. In the embodiment illustrated two such abutment means are provided for alternative use, depending upon the distance of the drill hole from the leading end of the chord. Thus, if the distance is greater than a predetermined minimum, the stop member 108 is used. This stop member comprises a rod carried by a block 110 mounted slidably on an elongated bar 112 which is positioned above and extends substantially parallel to the rail 12. This bar, and a similar bar 114 adjacent the other rail 14, are provided with graduations to facilitate the positioning of the stop components supported thereon.

The block 110 is provided with a transverse bore which slidably receives the stop rod 108. The outer end of the rod is provided with a hand knob 116 by which the rod is moved laterally inward against the resistance of the retracting spring 118. A set screw is threaded into the block for releasable engagement with the bar 112, to secure the block in adjusted positions.

By pressing inward on the knob 116 the inner end of the rod is moved to intercept the path of travel of the truss joist chord,

thereby providing an end abutment to position the chord for drilling the first hold. When the chord is brought into abutment with the rod, the latter may be allowed to retract to the position illustrated in FIG. 1, by the force of the spring 118. The chord is clamped firmly between the clamp members 74 and 86 during the drilling operation.

If the first hole is to be drilled closer to the leading end of the chord than is permitted by adjustment of the stop 108, the auxiliary stop best illustrated in F IG. 6 is employed. This stop comprises an elongated threaded screw 120 mounted in a threaded opening in the lug 122 projecting upward from the horizontal leg 124 of the angle bracket. The vertical leg 126 of the bracket is received slidably in a slot provided by the channel member 128 secured to the framework 10. A longitudinal extension 124 on the horizontal leg of the bracket serves as a handle by which to elevate the stop screw to the broken line position for intercepting the path of movement of a chord. The screw may be adjusted longitudinally to positions closer to the drill assemblies than the previously mentioned stop member 108.

After the first hole is drilled in the chord, the latter is moved forward to a router component for slotting the chord in the area of the drilled hole. The router component includes a carriage 130 mounted for longitudinal movement on the rails 12 and 14 by means described in detail hereinafter. A rotary router assembly is supported by the'carriage in the manner best shown in FIG. 7. Thus, a shaft 132 is supported for pivotal movement on the carriage and mounts one end of a router blade arm 134 secured thereto by the set screw 136. The opposite end of the arm is connected pivotally, as by the pin 138, to the projecting end of the piston rod 140. The opposite end of the piston rod is secured to a piston within the hydraulic cylinder 142. The end of the cylinder opposite the piston rod is mounted pivotally, as by the pin 144,,on a flange secured to the carriage. i

Intermediate the ends of the arm the shaft 146 mounts the rotary router blade 148. The shaft also supports a pulley 150 (FIG. 8) for rotation with the blade, and this pulley is connected operatively through the belt 152 to a double pulley 1S4 journaled for independent rotation on the shaft 132. The double pulley also is connected operatively through the belt 156 to a pulley 158 mounted on the output shaft 160 of the electric drive motor 162 supported by the carriage.

Accordingly, the router blade is driven rotationally by the motor and is moved between the retracted position illustrated in full lines in FIG. 7 and the operative, routing position illustrated in broken lines, by appropriate application of hydraulic pressure through the conduits 164 and 166 to opposite ends of the cylinder 142. Sawdust produced by such routing is removed through the vacuum conduits 168 communicating with the interior of the carriage.

It is usual practice in the manufacture of truss joists to make the two openings adjacent each end of the chord larger in diameter than the intermediate drill openings. It is also desirable that the slots associated with the larger drill openings be wider than the slots associated with the smaller, intermediate drill openings. Accordingly, means is provided for varying the width of the slots in relation to the diameter of the openings. Referring particularly to FIG. 8, the shaft 132 mounting the router arm 134 is mounted at one end in a bearing 170 which allows a limited degree of axial displacement of the shaft. The opposite end of the shaft is coupled to the projecting end of a piston rod 172. The opposite end of the piston rodis secured to a piston contained in the hydraulic cylinder 174 secured to the carriage. Thus, by appropriate applications of hydraulic pressure t'o opposite ends of the cylinder, by means of conduits 176 and 178 (FIG. 18), the shaft may be moved axially through a limited distance defined in one direction by abutment of the facing surfaces of the bearing 170 and the arm hub shoulder 180 and in the opposite direction by abutment of the gearing 182 and retainer ring 184. This distance provides the desired increased width of the slot associated with the larger diameter drill opening. Controlled operation of the hydraulic cylinder is described in detail hereinafter.

Means is provided for positioning the truss joist chord accurately so that the router blade will slot the chord symmetrically with respect to the drilled opening. Thus, a mounting block 190 is secured in fixed position on the carriage. Secured to the mounting block, by means of the bolt 192, is a stop block 194 which supports an index 196 arranged to register with the graduated bar 114. The stop block is provided with a transverse bore which slidably receives the stop pin 198 provided at its outer end with a hand knob 200. The inner end of the pin is stepped in diameter to provide two sections, the terminal section 202 corresponding to the diameter of the smaller drill openings to be provided in the chord, and the next inner stepped section 204 corresponding to the diameter of the larger drill opening to be provided in the chord.

The axis of the stop pin is located vertically above the axis of the router blade mounting shaft 146 (FIG. 7) when the blade is in its elevated, operative position. Accordingly, the slot routed into the chord is substantially symmetrical with respect to the drilled opening.

The carriage 130 is adjusted along the rails 12 and 14 so that the distance between the stop pin 198 and the drill 44 or 44 is equal to the desired spacing between the first and second drill openings.

Means is provided for adjusting the carriage on the rails with a high degree of accuracy so as to establish precisely the desired distance between drill openings. Thus, a micrometer block 210 is secured in fixed position to the rails 12 and 14 and is provided with a longitudinal bore. The bore mounts a micrometer nut 212 for rotation relative thereto while preventing relative axial displacement. The bore also mounts a lock nut 214 for relative rotation while preventing relative axial displacement. The micrometer nut and lock nut are provided with axially alined threaded bores which receive therethrough the elongated micrometer screw 216. The rearward end of the micrometer screw is provided with an enlarged head 218. The head abuts the leading end of the carriage and is clamped securely thereto by the clamp plates 220 (FIG. 12).

The micrometer screw and nut are threaded in such manner that one complete revolution of the micrometer. nut moves the carriage a distance equal to the spacing between graduations on the bar 114. The micrometer nut is provided with graduations which are referenced to an index mark on the micrometer block. The initial setting of the micrometer to zero graduation is effected by loosening the clamps 220, alining the zero graduation on the micrometer nut with its index mark and then rotating the micrometer screw to move the carriage until the index 196 is alined precisely with one of graduations on the bar. The clamps then are securely tightened to prevent rotation of the micrometer screw.

The carriage also mounts a reference guide roller 104' and a cooperating spring loaded press roller 106', similar to the rollers 104 and 106 described hereinbefore.

After the simultaneous routing of the chord in the area of the first drill hole and the drilling of the second hole, the chord is advanced until the second drill hole is alined with the stop pin 198. The latter then is pushed inward into the second drill hole, whereupon the router assembly and appropriate drill assembly are activated simultaneously to effect routing of the chord in the area of the second drill hole and to effect drilling of the third hole, respectively. This procedure is repeated until all drill holes and slots have been provided in the chord. The last drill hole then is positioned for engagement by the cutoff stop 222, similar to stop pin 1%, which has been secured to the rail 14 in properly adjusted position relative to the cutoff unit 224, for trimming the trailing end of the chord.

The cutoff unit (FIG. 14) is mounted on the framework and is of conventional construction. It includes an overhead support track 226 which mounts a traveling cutoff saw and drive assembly for reciprocating a rotary saw blade 228 transversely across the chord. I

The outfeed end of the framework also supports a horizontal roller 16 and a cooperating vertical reference guide roller 18, similar to the rollers 16 and 18 located at the infeed end of the framework.

Additional stop members 230 are mounted on the rails for alternative use, rather than the main stop 198, when it is desired to vary the spacings between some of the drill holes. These auxiliary stop members are substantially the same construction as the main stop. However, they may include a retracting spring 232, for the same purpose as spring 118 associated with the first abutment stop 108.

In some instances it may be desired to interrupt the manufacture of a plurality of chords to run a special chord having different spacing between drill openings. In such instance, rapid readjustment of the apparatus may be effected simply by loosening the bolt 192 which secure the stop block 1 94 to the mounting block and interposing between them a shim plate 234 (FIGS. 10 and 11) of predetermined thickness. By so doing, the main stop 198 is moved a corresponding distance closer to the operational axis of the drill assembly, to accommodate correspondingly closer drill opening spacings. Normally, a shim plate is interposed between the blocks 190and 194 so that its removal or replacement by a thinner shim plate accommodates increasing the spacing between drill openings.

FIG. 16 illustrates a typical construction of a parallel chord truss joist, and FIG. 17 illustrates a typical construction of a conventional bow-type truss joist. In the parallel chord type truss the spacings between adjacent drill openings in the upper and lower chords are the same, whereas in the bow-type truss the spacings between adjacent openings in the lower chord are shorter than those in the upper chord. Accordingly, it is the usual practice to manufacture a plurality of chords having the same spacings between drill openings, and then to readjust the apparatus for the mass production of chords in which the spacings between drill openings are different. The apparatus is adjusted by loosening the lock nut 214 and rotating the micrometer nut 212 in the appropriate direction sufficiently to move the carriage a distance corresponding to the desired difference in drill openings spacings. The lock nut then is tightened, whereupon the apparatus is ready for operation.

FIG. 18 illustrates schematically the electrical circuitry and associated hydraulic system by which operation of the apparatus is controlled automatically to assure that the router slots are properly related in position and width to the different sizes of drill openings. The arrangement illustrated is best described with reference to operation of the apparatus, as follows:

The operator places a chord C in position on the infeed rolls and moves it forward until its leading end abuts one or the other of the stops which has been moved to intercept the chord. The operator then presses the master switch button 240 on the control panel P mounted on the carriage 130. Closure of the master switch contact A thus completes the electric circuit of the coil 242 of the solenoid valve 244 to shift the latter to apply hydraulic pressure to the clamp cylinders 70 and 94 to draw the clamps together and secure the chord for drilling. Closure of the master switch contact A and the push button control switch 246 for the drill component also completes the electric circuit of the larger drill motor 24 and the extend coil 248 of the associated solenoid valve 250. Hydraulic pressure thus is delivered through conduit 56 against the advance piston 50, whereupon the rotating drill 44 is extended inward through the chord to drill the first larger opening.

Upon full extension of the drill the actuating arm 252 (FIG. 3) of the switch assembly engages the cam surface 64 and effects closure of the associated switches 254 and 256. Closure of the switch 256 completes the electric circuit of the retract coil 260 of the larger drill solenoid valve 250, whereupon hydraulic pressure is delivered through conduit 54 against the retract piston 48 to return the drill to its retracted position.

Simultaneously, closure of the switch 254 completes the electric circuit of the stepper relay coil 262. Activation of this coil operates to step the contact 264 of the stepping switch 266 clockwise from the zero position illustrated to the next adjacent position.

It is to be pointed out here that the contact 268 of the selector switch 270 will have been set initially to the position designating the number of larger drill openings to be made in sequence. For example, referring to FIG. 15, it is to be noted that there are two larger drill openings at each end of a chord. Therefore the selector switch will be set initially to provide two larger drill openings, After these have been drilled, the selector switch will be reset manually to provide four larger drill openings, to effect drilling of the two larger holes at the trailing end of the first chord and the two larger drill openings at the adjacent leading end of the next succeeding chord.

The selector switch 272 associated with the stepping switch 274 for the smaller drill assembly is shown to be set for five smaller drill openings, to provide the chord illustrated in FIG. 15.

Upon retraction of the drill assembly 22 to the position illustrated in FIG. 3 the cam surface 62 on the retract piston actuates the arm 276 to close the switch 278. The electric circuit of the coil 280-associated with the solenoid valve 244 of the clamp assembly is energized to connect the cylinders 70 and 94 to the exhaust reservoir conduit 282. The springs 82 and 98 associated with the pistons thus operate to retract the clamp members and release the chord.

The operator now moves the chord forward to aline the first drill opening with the router stop 198, whereupon the latter is pushed inward to engage the opening and thus secure the chord in proper alinement for the routing operation as well as for the drilling of the second hole. The operator then depresses the master switch pushbutton 240 to effect drilling of the second larger hole, by repeat of the steps previously described, and simultaneously to effect routing of the chord in the area of the first drilled hole.

Upon closure of the master switch the electric circuit is completed through the normally closed contact B of the router control relay 284 and through the coil 286 of the router control solenoid valve 288. Hydraulic pressure thus is applied through conduit 178 to the wide rout cylinder 174 to effect extension of the associated piston rod 172 and movement of the pivot shaft 132 (FIG. 8) toward the right until shoulder 180 abuts the bearing 170. The router blade 148 thus is moved toward the right from its normal position, for the purpose of routing a wider slot for the first large drill opening.

The operator now closes the router control switch 290 to complete the electric circuit of the coil 292 of the solenoid valve 294 associated with the cylinder 142, whereupon the piston is driven upward (FIG. 7) to elevate the rotating router blade into the chord to cut the first portion of the slot.

When the cylinder has elevated the router blade to its limit, the finger 296 (F168. 8 and 9) secured to the pivot shaft 132 will have been rotated clockwise into engagement with the actuator 298 of the switch 300, closing the contacts of the latter to complete the electric circuit of the coil 302 of the solenoid valve 294. Hydraulic pressure thus is applied to the upper end of the cylinder 142 to retract the piston and the connected router blade 148 to the position illustrated in full lines in FIG. 7. In this retracted position the finger 296 is rotated counterclockwise to the broken line position illustrated in FIG. 9, closing the contacts of the switches 304 and 306. Closure of the switch 304 completes the electric circuit of the coil 308 of the solenoid valve 288 to effect retraction of the piston in the wide router cylinder 174, moving the pivot shaft 132 leftward to the position illustrated in FIG. 8. Simultaneously, closure of the switch 306 completes the electric circuit of the coil 292 of the solenoid valve 294 to effect upward movement of the router blade into the chord, as previously described. The second section of the router slot thus is completed, whereupon the router blade is retracted by activation of the solenoid valve coil 302 upon closure of the switch 300.

Having completed the routing of the chord in the area of the first drill hold and the drilling of the second larger hole, activation of the stepper relay coil 262, by return of the drill to retracted position, effects stepping of the stepping switch264 to the second contact which matches the setposition of the selector switch 270. The electric circuit of the drill flip-flop relay coil 310 is completed, to switch the associated contacts to the alternate positions from those illustrated, and also completes the electric circuit of the stepper reset relay coil 312 to return the stepping switch 266 to its initial zero position. Since, in the chord construction illustrated in H6. 15, the next series of larger holes to be drilled will be four in number, the operator now resets the selector switch 270 to the No. 4 contact.

Upon activation of the drill flip-flop relay coil 310 and consequent switching of the associated contacts the apparatus is in readiness to effect activation of the smaller drill assembly. Accordingly, the operator retractsthe stop member 198 and moves the chord longitudinally forward to aline the second larger drill opening with said stop member. The latter then is extended into the opening to secure the chord in position for drilling.

The operator then depresses the master switch push button 240 to complete the electric circuit of the coil 3l4 of the solenoid valve 316 associated with the smaller drill assembly 20 and also the coil 242 of the solenoid valve 244 associated with the clamp mechanism. Thelatter thus is activated to secure the chord during drilling of the first smaller drill opening.

Simultaneously with the drillingof the first smaller opening, the router assembly is shifted to the wide rout position, upon activation of the coil 286 associated with the solenoid valve 288, and the router blade 148 is elevated to cut the first section of the slot, by activation of the coil 292 of the solenoid valve 294. The first section of the slot associated with the second larger drill opening thus is made, whereupon the router blade is retracted, shifted laterally to its normal position upon closure of the switch 304, and then raised to cut the second section of the slot, as previously described.

As the smaller drill 44' reaches its extended position, the as-. sociated cam 64, similar to the cam 64 associated with the larger drill assembly, moves the switch arm 252' to effect closure of the switches 318 and 320. Closure of the switch 318 completes the electric circuit of the stepper relay coil 322 which thereupon steps the stepping switch 274 to the first contact position. Closure of the other switch 320 completes the electric circuit of the coil 324 of the solenoid valve 316 to effect retraction of the drill 44.

Closure of the switch 320 also completes the electric circuit of the router flip-flop relay coil 284, thereby transferring the associated contacts to the alternate positions from those illustrated. Opening of the contact B breaks the electric circuit of the coil 286 of the wide rout solenoid valve 288, thereby insuring that subsequent routings will be the narrower slots for the smaller drill openings.

Upon retraction of the smallerdrill assembly, the cam 62 similar to the cam 62 associated with the larger drill assembly, engages a switch contact 276' to effect closure of the switch 326. This completes the electric circuit of the coil 280 of the solenoid valve 244 to effect release of the clamp mechanism.

The operator repeats the foregoing sequence of steps to complete the drilling and routing of the remaining four smaller drill openings. Thereupon the stepping switch 274 will have been moved to the contact matching the contact set on the selector switch 272. This complete the electric circuit of the coil 310 of the drill flip-flop relay, transferring the associated contacts back to the positions illustrated, and also the coil 328 of the stepper reset relay which thereupon resets the stepping switch 274 to it initial zero position.

The operator then moves the chord forward, as before, depresses the master switch push button 240 to effect clamping of the chord and extension of the larger drill 44 to drill the third larger opening. Simultaneously therewith the router assembly is activated to rout the slot in the area of the last smaller drill opening. Since the router flip-flop relay 284 is deenergized, the router blade 148 is retained in the normal position for routing the narrower slot.

However, upon extension of the larger drill 44, closure of the switch 256 effects activation of the coil 284 and consequent shifting of its associated contacts back to the positions illustrated. Accordingly, closure of the contact B enables subsequent activation of the coil 286 of the solenoid valve 288 to shift the router to the wide rout position. This is efiected by subsequent closing of the master switch 240 after the chord has been moved forward to the position of drilling the fourth and last larger opening in the chord.

After the hole has been drilled in the chord the latter is moved to engage the stop member 198 in said last opening. The drill control switch 246 is opened, to deactivate the drill component, and then the master switch is closed to effect wide routing of the chord in the area of the last larger drill opening.

The chord then is moved longitudinally forward to engage the cutoff stop member 222 in the last larger drill opening. This stop member is secured to the bar 114 in appropriately adjusted position relative to the plane of travel of the cutoff saw 228, to effect trimming of the trailing end of the chord to desired length.

From the foregoing it will be appreciated that the present invention provides apparatus by which to effect the drilling and routing of truss joist chords with speed and precision. The possibility of errors in drilling and routing are minimized by electrical circuitry correlating the router shifting mechanism with the larger drill assembly. The micrometer adjustment for the carriage accommodates rapid and precise readjustment of the position of the router stop member and associated router, for changing the spacing between drill openings for chords of various types and sizes. The quickly changeable shim member also provides the advantage of temporarily changing the position of the stop member, to interrupt a production schedule to make one or a few of a special size of chord, and thereafter to quickly return to a previous setting to resume former production.

It will be apparent to those skilled in the art that various changes in the size, shape, number and arrangement of parts described hereinbefore may be made without departing from the spirit of this invention.

I claim:

1. Apparatus for drilling and routing truss joist chords, comprising:

a. a framework;

b. support means on the framework for guiding a chord for longitudinal movement relative to the framework;

c. retractable drill means supported by the framework and movable to drill a hole through a chord;

first retractable stop means supported by the framework and movable to intercept the path of movement of a chord to position the latter relative to the drill means;

e. retractable router means supported by the framework and movable to rout a slot in a chord;

f. second retractable stop means supported by the framework and movable to intercept the path of movement of a chord to position a previously drilled hole in substantial alinement with the router means; arid g. shift means supported by the framework andangaging the router means for moving the latter laterally for routing a slot wider than the router means.

2. The apparatus of claim 1 wherein the second stop means comprises a retractable pin having a chord intercepting end adapted for reception in a drill opening in the chord, the pin being positioned substantially in alinement with the router means.

3. The apparatus of claim 1 wherein:

a. the drill means comprises a pair of drill assemblies for drilling holes of different diameters;

b. operator means is associated with each drill assembly for moving the latter;

c. operator means is associated with the shift means for moving the latter; and d. control means is associated with both said operator m'eans for moving the shift means automatically to rout said wider slot in the areas of the larger drill holes.

4. The apparatus of claim 1 including:

a. a carriage mounted on the framework for longitudinal adjustment and supporting the router means, second stop means and shift means; and I b. micrometer adjustment means interengaging the carriage and framework for adjusting the carriage longitudinally with respect to the drill means.

5. The apparatus of claim 4 including index means on the carriage in registry with longitudinally spaced graduations on the framework, the micrometer adjustment means having a threaded screw arranged in one revolution to move the carriage a distance equal to the spacing between graduations on the framework.

6. The apparatus of claim 4 including adjustable mounting means supporting the second stop means on the carriage for longitudinal adjustment relative to the drill means. 

